LAUSR

Abstract The metallostibine Os 2 (CO) 8 ( μ -SbPh), 2 , acts as a good two-electron donor ligand, reacting readily with Group 8 metal carbonyls to give heterometallic clusters. Specifically, it undergoes ligand substitution reaction with Fe 2 (CO) 9 , Os 3 (CO) 11 (CH 3 CN), or Os 3 (CO) 10 (CH 3 CN) 2 to afford Os 2 Fe(CO) 12 ( μ 3 -SbPh), 3 , Os 5 (CO) 19 ( μ 3 -SbPh), 4 , or Os 7 (CO) 26 ( μ 3 -SbPh) 2 , 5 , respectively, in moderate to high yields. An analogous reaction with Ru 3 (CO) 11 (CH 3 CN) afforded another spirocyclic cluster Os 3 Ru(CO) 14 ( μ -PhCO)( μ 4 -Sb), 9 . UV irradiation of 4 afforded the spirocyclic clusters Os 5 (CO) 18 ( μ , η 2 -PhCO)( μ 4 -Sb), 6 , and Os 5 (CO) 18 ( μ , η 2 -C 6 H 4 )( μ -H)( μ 4 -Sb), 7 , while the raft-like cluster Os 5 (CO) 19 ( μ 3 -SbPh), 8 , was obtained when a methanolic solution was exposed to natural light; cluster 5 failed to react under similar conditions. All the new clusters have been characterized spectroscopically and crystallographically, and possible pathways for the formation of 6 - 9 proposed.